/Engine/Source/Runtime/Engine/Classes/Engine/Texture.h
Calculate the combined LOD bias based on texture LOD group and LOD bias. CalculateLODBias(true) >= CalculateLODBias(false) CalculateLODBias(true) == CalculateLODBias(false) + NumCinematicMipLevels , except when a clamp was applied
LOD bias
int32 CalculateLODBias ( bool bWithCinematicMipBias ) const